SPRAY DRYING PROCESS FOR MAKING A LOW OR NIL PHOSPHATE AUTOMATIC DISHWASHING DETERGENT COMPOSITION

Abstract: The present invention relates to a process for making a high bulk density granular automatic dishwashing detergent composition comprising spray drying a mixture of alkali metal silicate and water soluble organic polymer. The spray dried granule is combined with conventional nonphosphate automatic dishwashing detergent ingredients to form a final product.

Description: Spray dryi ng process for making a low or ni l phosphate automatic di shwashi ng detergent composi tion TECHNICAL FIELD The present invention relates to a process for spray drying components of high bulk density low or nil phosphate granular automatic dishwashing detergent compositions. In particularly, the invention relates to forming granules by spray drying alkali metal silicate and water-soluble polymer. BACKGROUND OF THE INVENTION Granular automatic dishwashing detergent compositions and their components, e.g. builders, alkaline salts, sodium silicate, low-foaming surfactants, chlorine bleach, etc. , are well known in the art. A number of processes have been described for the production of such dishwashing detergent compositions. Generally, agglomeration and/or admixing techniques are used in manufacturing a granular automatic dishwashing detergent composition. For example, U.S. Patent 4,379,069, Rapisarda et al., issued April 5, 1983, U.S. Patents 4,427,417, Porasik, issued January 24, 1984, and 3,888,781, Kingry et al., issued June 10, 1975. However, because of the demand for compact detergent compositions, alternate means must be found for incorporating high levels of liquid components (i.e. nonionic surfactant, polyacrylate, and the like) as the amount of solid components decreases. Spray drying techniques have been employed in producing laundry detergents; however, spray drying processes have not been extensively applied to automatic dishwashing detergents because the process often results in low bulk density products. In addition, because of phosphate reversion during spray drying (resulting in insoluble residue) this process had been avoided for traditional phosphate containing automatic dishwashing detergent formulas. It has now been found that a nil or low-phosphate, high bulk density granular automatic dishwashing detergent composition can be achieved by spray drying an aqueous mixture of alkali metal silicate and water-soluble organic polymer (i.e. polyacrylate) and combining the resulting granule with nonphosphate automatic dishwashing detergent ingredients. The ingredients may be combined by post admixing dry solids and/or agglomerating to achieve the desired high bulk density product of greater than about 0.7 grams/cc. Surprisingly, the compositions can clean dishware as effectively as phosphate containing compositions. SUMMARY OF THE INVENTION The present invention encompasses processes for making low or nil phosphate, high bulk density granular automatic dishwashing detergent composition comprisirs;: (a) spray drying a mixture comprising from about 20% to about 90%, by weight of said mixture, of alkali metal silicate solution and from about 5% to about 30%, by weight of said mixture, of water-soluble organic polymer solution to form free flowing granules; and (b) combining from about 20% to about 80%, by weight of said composition, of said granules of step (a) with from about 1 % to about 90% of non-phosphate detergent builder; wherein said composition has a bulk density of greater than about 0.7 grams/cc and less than about 0.5% phosphate in the form of phosphorous. Preferably a concentrated product is desired wherein the spray dried granules and non-phosphate detergent builder are admixed. The composition also preferably comprises nonionic surfactant, enzymes and oxygen bleach. DETAILED DESCRIPTION OF THE INVENTION The granular detergent composition process of the present invention comprises spray drying a mixture of alkali metal silicate and water-soluble organic polymer to form free flowing granules; and combining said granules with non- phosphate detergent builder. Low foaming nonionic surfactant and bleach are preferable optional ingredients. The component materials are described in detail below. Alkali Metal Silicate The compositions of the type described herein deliver their bleach and alkalinity to the wash water very quickly. Accordingly, they can be aggressive to metals, dishware, and other materials, which can result in either discoloration by etching, chemical reaction, etc. or weight loss. The alkali metal silicates hereinafter described provide protection against corrosion of metals and against attack on dishware, including fine china and glassware. The SiO level should be from about 4% to about 25%, preferably from about 5% to about 20%, more preferably from about 6% to about 15%, based_qn_ the weight of the automatic dishwashing detergent composition. The ratio of SiO ^ to the alkali metal oxide (M O, where M=alkali metal) is typically from about 1 to about 3.2, preferably from about 1.6 to about 3, more preferably from about 2 to about 2.4. The alkali metal silicate is an aqueous solution, having from about 30% to about 60%, more preferably from about 40% to about 50% water. The present invention comprises spray drying a mixture containing water- soluble organic polymer discussed herein below and from about 20% to about 90%, preferably from about 40% to about 70% alkali metal silicate solution. Water-soluble Organic Polymer The water soluble organic polymer, is employed in the present invention at levels from about 0.1% to about 20%, preferably from about 1% to about 10%, most preferably from about 3% to about 8%, by weight of the composition. The water-soluble organic polymer is in aqueous solutions and can be alkali metal salts of a polycarboxylic acid. The aqueous solution of a water-soluble polymer can comprise from about 10% to about 70%, preferably from about 20% to about 60%, more preferably from about 30% to about 50%, most preferably from about 40% to about 50%, by weight of the water-soluble polymer of water. The aqueous solution of a water- soluble polymer comprises from about 5% to about 30%, by weight of the spray dry mixture. Solutions of the film-forming polymers described in U.S. Pat. No. 4,379,080 (Murphy), issued Apr. 5, 1983, incorporated herein by reference, can be used as the water-soluble organic polymer of the present invention. Suitable polymers for use in the aqueous solutions are at least partially neutralized or alkali metal, ammonium or substituted ammonium (e.g., mono-, di- or triethanolammonium) salts of polycarboxylic acids, excluding those with potential flammability or explosive properties. When the sodium silicate and polymer are spray dried together the acid form of the polymer should be avoided so that interaction with the silicate does not occur. The alkali metal, especially sodium "salts are most preferred. While the molecular weight of the polymer can vary over a wide range, it preferably is from about 1,000 to about 500,000, more preferably from about 2,000 to about 250,000, and most preferably is from about 3,000 to about 100,000. Other suitable polymers include those disclosed in U.S. Patent No. 3,308,067 issued March 7, 1967, to Diehl, incorporated herein by reference. Unsaturated monomeric acids that can be polymerized to form suitable polymeric polycarboxylates include acrylic acid, maleic acid (or maleic anhydride), fumaric acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid and methylenemalonic acid. The presence of monomeric segments containing no carboxylate radicals such as vinylmethyl ether, styrene, ethylene, etc. is suitable provided that such segments do not constitute more than about 40% by weight of the polymer. Other examples of suitable polymers for use herein are copolymers of ε /lamide and acrylate having a molecular weight of from about 3,000 to about 100,000, preferably from about 4,000 to about 20,000, and an acrylamide content of less than about 50%, preferably less than about 20%, by weight of the polymer. Most preferably, the polymer has a molecular weight of from about 4,000 to about 20,000 and an acrylamide content of from about 0% to about 15%, by weight of the polymer. Particularly preferred are aqueous solutions of polyacrylates with an average molecular weight in acid form of from about 1,000 to about 10,000, and acrylate/maleate or acrylate/fumarate copolymers with an average molecular weight in acid form of from about 2,000 to about 80,000 and a ratio of acrylate of maleate or fumarate segments of from about 30:1 to about 2:1. This and other suitable copolymers based on a mixture of unsaturated mono- and dicarboxylate monomers are disclosed in European Patent Application No. 66,915, published December 15, 1982, incorporated herein by reference. Other polymers useful herein include the polyethylene glycols and polypropylene glycols having a molecular weight of from about 950 to about 30,000 which can be obtained from the Dow Chemical Company of Midland, Michigan. Such compounds for example, having a melting point within the range of from about 30o to about lOOoC can be obtained at molecular weights of 1450, 3400, 4500, 6000, 7400, 9500, and 20,000. Such compounds are formed by the polymerization of ethylene glycol or propylene glycol with the requisite number of moles of ethylene or propylene oxide to provide the desired molecular weight and melting point of the respective polyethylene glycol and polypropylene glycol. The polyethylene, polypropylene and mixed glycols are conveniently referredTo by means of the structural formula CH. CH HO-(CH -CH O) -(CH -CHO) -(CH-CH 0) -H 2 2 m 2 n 2 o wherein m, n, and o are integers satisfying the molecular weight and temperature requirements given above. Other polymers useful herein include the cellulose sulfate esters such as cellulose acetate sulfate, cellulose sulfate, hydroxyethyl cellulose sulfate, methylcellulose sulfate, and hydroxypropylcellulose sulfate. Sodium cellulose sulfate is the most preferred polymer of this group. Carboxylated polysaccharides are also suitable polymers, particularly starches, celluloses and alginates, described in U.S. Pat. No. 3,723,322, Diehl, issued Mar. 27, 1973; the dextrin esters of polycarboxylic acids disclosed in U.S. Pat. No. 3,929, 107, Thompson, issued Nov. 11, 1975; the hydroxyalkyl starch ethers, starch esters, oxidized starches, dextrins and starch hydrolysates described in U.S. Pat No. 3,803,285, Jensen, issued Apr. 9, 1974; and the carboxylated starches described in U.S. Pat. No. 3,629,121, Eldib, issued Dec. 21, 1971; and the dextrin starches described in U.S. Pat. No. 4,141,841, McDanald, issued Feb. 27, 1979; all incorporated herein by reference. These polymers are also often referred to as thickeners. Preferred polymers of the above group are the carboxymethyl celluloses. Other useful polyacrylates are The term modified polyacrylate is defined as a copolymer which contains as monomer units: a) from about 90% to about 10%, preferably from about 80% to about 20% by weight acrylic acid or its salts and b) from about 10% to about 90%, preferably from about 20% to about 80% by weight of a substituted acrylic monomer or its salts having the general formula: R R . 2 .1 - [ C - C ] - C = O O I a hydrogen or alka meta sa t. Most pre erre s a su st tuted acrylic monomer wherein R is methyl, R is hydrogen and R is sodium. The low molecular weight polyacrylate preferably has a molecular weight of less than about 15,000, preferably from about 500 to about 10,000, most preferably from about 1,000 to about 5,000. The most preferred polyacrylate copolymer has a molecular weight of 3500 and is about 70% by weight acrylic acid and about 30% by weight methyl acrylic acid. Suitable modified polyacrylate copolymers include the low molecular weight copolymers of unsaturated aliphatic carboxylic acids as disclosed in U.S. Patent 4,530,766, and 5,084,535, both of which are incorporated herein by reference. In general, the water-soluble organic polymer can comprise any one or a mixture of the polymers described above. Non-phosphate Detergency Builder The detergency builders used can be any of the non-phosphate detergency builders known in the art, which include the various water-soluble, alkali metal, ammonium or substituted ammonium carbonates, borates, polyhydroxysulfonates, polyacetates, carboxylates (e.g. citrates), and polycarboxylates. Preferred are the alkali metal, especially sodium, salts of the above and mixtures thereof. The builder is present in the automatic dishwashing detergent composition in an amount from about 1 % to about 90%, preferably from about, 5% to about 80%, most preferably 15% to about 75%, by weight, of the automatic dishwashing detergent composition. Examples of non-phosphorus, inorganic builders are sodium and potassium carbonate, bicarbonate, sesquicarbonate and hydroxide. Water-soluble, non-phosphorus organic builders useful herein include the various alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxysulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, po isium, lithium, ammonium and substituted ammonium salts of ethylene diamine tetraacetic acid, nitrilotriacetic acid, tartrate monosuccinic acid, tartrate disuccinic acid, oxydisuccinic acid, carboxy methyloxysuccinic acid, mellitic acid, benzene polycarboxylic acids, and citric acid. Preferred detergency builders have the ability to remove metal ions other than alkali metal ions from washing solutions by sequestration, which as defined herein includes chelation, or by precipitation reactions. Although sodium tripolyphosphate has generally been a particularly preferred detergency builder material, sodium citrate is preferred to reduce the total phosphorus level of the compositions of the invention. Particularly preferred automatic dishwashing detergent compositions of the invention contain, by weight of the composition, from about 5% to about 40%, preferably from about 10% to about 30%, most preferably from about 15% to about 25%, of sodium carbonate. Particularly preferred sodium citrate with levels from about 5% to about 40%, preferably from about 7% to 30%, most preferably from about 8% to about 20%, by weight of the composition are also present. Low Foaming Nonionic Surfactant The low foaming nonionic surfactants of the present invention are from about 0.1 % to about 10%, preferably from about 0.5% to about 5%, by weight of the composition. Herein, by "low foaming" is meant that the nonionic surfactant is suitable for use in an automatic dishwasher. Reduced surfactant mobility is a consideration in stability of the optional bleach component. Preferred surfactant compositions with relatively low solubility can be incorporated in compositions containing alkali metal dichlorocyanurates or other organic chlorine bleaches without an interaction that results in loss of available chlorine. The nature of this problem is disclosed in U.S. Patent 4,309,299 issued January 5, 1982 to Rapisarda et al and in U.S. Patent 3,359,207, issued December 19, 1967, to Kaneko et al, both patents being incorporated herein by reference. In a preferred embodiment, the surfactant is an ethoxylated surfactant derived from the reaction of a monohydroxy alcohol or alkylphenol containing from about 8 to about 20 carbon atoms, excluding cyclic carbon atoms, with from about 6 to about 15 moles of ethylene oxide per mole of alcohol or alkyl phenol on an average basis. A particularly preferred ethoxylated nonionic surfactant is derived from a straight chain fatty alcohol containing from about 16 to about 20 carbon atoms (C alcohol), preferably a C alcohol, condensed with an average of from 16-20 18 about 6 to about 15 moles, preferably from about 7 to about 12 moles, and most preferably from about 7 to about 9 moles of ethylene oxide per mole of alcohol. Preferably the ethoxylated nonionic surfactant so derived has a narrow ethoxylate distribution relative to the average. The ethoxylated nonionic surfactant can optionally contain propylene oxide in an amount up to about 15% by weight of the surfactant and retain the advantages hereinafter described. Preferred surfactants of the invention can be prepared by the processes described in U.S. Patent 4,223,163, issued September 16, 1980, Guilloty, incorporated herein by reference. The most preferred composition contains the ethoxylated monohydroxyalcohol or alkyl phenol and additionally comprises a polyoxyethylene, polyoxypropylene block polymeric compound; the ethoxylated monohydroxy alcohol or alkyl phenol nonionic surfactant comprising from about 20% to about 80%, preferably from about 30% to about 70%, of the total surfactant composition by weight. Suitable block polyoxyethylene-polyoxypropylene polymeric compounds that meet the requirements described hereinbefore include those based on ethylene glycol, propylene glycol, glycerol, trimethylolpropane and ethylenediamine as the initiator reactive hydrogen compound. Polymeric compounds made from a sequential ethoxylation and propoxylation of initiator compounds with a single reactive hydrogen atom, such as C aliphatic alcohols, do not provide satisfactory suds control in the detergent compositions of the invention. Certain of the block polymer surfactant compounds designated PLURONIC® and TETRONIC® by the BASF-Wyandotte Corp., Wyandotte, Michigan, are suitable in the surfactant compositions of the invention. A particularly preferred embodiment contains from about 40% to about 70% of a polyoxypropylene, polyoxyethylene block polymer blend comprising about 75%, by weight of the blend, of a reverse block co-polymer of polyoxyethylene and polyoxypropylene containing 17 moles of ethylene oxide and 44 moles of propylene oxide; and about 25%, by weight of the blend, of a block co-polymer of polyoxyethylene and polyoxypropylene, initiated with tri-methylol propane, containing 99 moles of propylene oxide and 24 moles of ethylene oxide per mole of trimethylol propane. Because of the relatively high polyoxypropylene content, e.g, up to about 90% of the block polyoxyethylene-polyoxypr pylene polymeric compounds of the invention and particularly when the polyoxypropylene chains are in the terminal position, the compounds are suitable for use in the surfactant compositions of the invention and have relatively low cloud points. Cloud points of 1% solutions in water are typically below about 32°C and preferably from about 15°C to about 30 °C for optimum control of sudsing throughout a full range of water temperatures and water hardnesses. Other Surfactants The composition herein can contain other surfactants. The surfactant can be present in the composition in an amount from about 0.1 % to about 10%, preferably from about 0.5% to about 5%, by weight of the composition. Suitable surfactants include anionic surfactants including alkyl sulfonates containing from about 8 to about 20 carbon atoms, alkyl benzene sulfonates containing from about 6 to about 13 carbon atoms in the alkyl group, and the preferred low-sudsing mono- and/or dialkyl phenyl oxide mono- and/or di- sulfonates wherein the alkyl groups contain from about 6 to about 16 carbon atoms are also useful in the present invention. All of these anionic surfactants are used as stable salts, preferably sodium and/or potassium. Other surfactants also include trialkyl amine oxides, betaines, etc. which are usually high sudsing. A disclosure of bleach-stable surfactants can be found in published British Patent Application No. 2,116,199A; U.S. Pat. No. 4,005,027, Hartman; U.S. Pat. No. 4,116,851, Rupe et al; and U.S. Pat. No. 4,116,849, Leikhim, all of which are incorporated herein by reference. Because of the high sudsing, suds suppressors discussed hereinbelow are also preferred. The preferred surfactants of the invention in combination with the other components of the composition provide excellent cleaning and outstanding performance from the standpoint of residual spotting and filming. In these respects, the preferred surfactants of the invention provide generally superior performance relative to ethoxylated nonionic surfactants with hydrophobic groups other than monohydroxy alcohols and alkyl-phenols, for example, polypropylene oxide or polypropylene oxide in combination with diols, triols and other polyglycols or diamines. Bleach Ingredient The compositions of the invention optionally contain an amount of bleach sufficient to provide the composition with from 0% to about 5%, preferably from about 0.1 % to about 5.0%, most preferably from about 0.5% to about 3.0%, of available chlorine or available oxygen based on the weight of the detergent composition. An inorganic chlorine bleach ingredient such as chlorinated trisodium phosphate can be utilized, but organic chlorine bleaches such as the chlorocyanurates are preferred. Water-soluble dichlorocyanurates such as sodium or potassium dichloroisocyanurate dihydrate are particularly preferred. The detergent compositions manufactured according to the present invention can contain bleach components other than the chlorine type. For example, oxygen-type bleaches described in U.S. Pat. No. 4,412,934 (Chung et al), issued Nov. 1, 1983, and peroxyacid bleaches described in European Patent Application 033,2259, Sagel et al, published Sept. 13, 1989, both incorporated herein by reference, can be used as a partial or complete replacement of the chlorine bleach ingredient described hereinbefore. These oxygen bleaches are particularly preferred when it is desirable to reduce the total chlorine content or use enzyme in the compositions of the invention. Other Optional Ingredients The automatic dishwashing compositions of the invention can optionally contain up to about 50%, preferably from about 2% to about 20%, most preferably less than about 5%, based on the weight of the surfactant, of an alkyl phosphate ester suds suppressor. Suitable alkyl phosphate esters are disclosed in U.S. Patent 3,314,891, issued April 18, 1967, to Schmolka et al, incorporated herein by reference. The preferred alkyl phosphate esters contain from 16-20 carbon atoms. Highly preferred alkyl phosphate esters are monostearyl acid phosphate or monooleyl acid phosphate, or salts thereof, particularly alkali metal salts, or mixtures thereof. The alkyl phosphate esters have been used to reduce the sudsing of detergent compositions suitable for use in automatic dishwashing machines. The esters are particularly effective for reducing the sudsing of compositions comprising nonionic surfactants which are block polymers of ethylene oxide and propylene oxide. Filler materials can also be present including sucrose, sucrose esters, sodium chloride, sodium sulfate, potassium chloride, potassium sulfate, etc., in amounts up to about 70%, preferably from 0% to about 40%. Perfumes (stable as to odn-Λ; dyes (such as those disclosed in U.S. Patent 4,714,562, Roselle et al, isst December 22, 1987); and enzymes and crystal modifiers and the like can also be added to the present compositions in appropriate amounts. Other commonly used detergent ingredients can also be included. Additional silicate may also be added to the composition in the form of solid silicate. Preferably, the solid alkali metal silicate is hydrous, having from about 15% to about 25% water, more preferably, from about 17% to about 20%. The highly alkaline metasilicates can be employed, although the less alkaline hydrous alkali metal silicates having a SiO :M O ratio of from about 2.0 to about 2.4 are preferred. Anhydrous forms of the alkali metal silicates with a SiO :M O ratio of 2.0 or more are less preferred because they tend to be significantly less soluble than the hydrous alkali metal silicates having the same ratio. Sodium and potassium, and especially sodium, silicates are preferred. A particularly preferred alkali metal silicate is a granular hydrous sodium silicate having a SiO :Na O ratio of from 2.0 to 2.4 available from PQ Corporation, named Britesil® H20 and Britesil® H24. Most preferred is a granular hydrous sodium silicate having a SiO -Na -atio of 2.0. 2 2 While typical forms, i.e. pc >er and granular, of hydrous silicate particles are suitable, preferred silicate particles have a mean particle size between about 300 and about 900 microns with less than 40% smaller than 150 microns and less than 5% larger than 1700 microns. Particularly preferred is a silicate particle with a mean particle size between about 400 and about 700 microns with less than 20% smaller than 150 microns and less than 1% larger than 1700 microns. Although some phosphate containing ingredients may be added to the composition, the present invention contains less than about 0.5% phosphate in the form of phosphorous. The Process In step (a), a mixture of 20% to about 90%, preferably from about 40% to about 70% , aqueous alkali metal silicate solution and from about 5% to about 30% aqueous polyacrylate solution, is spray dried to form free flowing granules. Applicable spray drying processes are described in U.S. Patents 4,715,979, Moore et al., issued December 29, 1987, 4,963,226, Chamberlain et al., issued October 16, 1990 and 4,344,871, Allaway et al., issued August 17, 1982 are incorporated herein by reference. Other ingredients may optionally be added to the mixture. Examples of suitable ingredients include alkali metal carbonates (i.e. sodium carbonate), nonionic surfactant, and fillers (i.e. sodium sulfate). Ingredients are selected for this step based upon their stability and safety. Safety protocols should be used to evaluate the thermostability, explosivity and degradation potential of the materials used during spray drying. The next step is to combine the spray dried granules of step (a) with non- phosphate detergency builder (i.e. sodium citrate), and optional ingredients (i.e. low foaming nonionic surfactant and bleaching agent), using any suitable batch or continuous mixing process, so long as a homogeneous mixture results therefrom. A preferred embodiment is an admixture containing a spray dried granule:non- phosphate detergency builder weight ratio of between about 1:20 and about 10: 1, respectively, more preferably between about 1:12 and about 5: 1, most preferably between about 1:3 and about 2: 1. An alternate method, where admixing the ingredients does not yield the desired product bulk density, consists of agglomerating the ingredients of step (b) and/or the granules of step (a) with ingredients of step (b). Agglomeration equipment which facilitates mixing and intimate contacting of a liquid binder (preferably selected from the group consisting of water, solutions of aqueous alkali metal salts of polycarboxylic acid, liquid silicate, nonionic surfactant and mixtures thereof) with dry detergent ingredients such that it results in agglomerated granulesr Suitable mixing devices include vertical agglomerators (e.g. Schugi Flexomix or Bepex Turboflex agglomerators), rotating drums, inclined pan agglomerators, O'Brien mixers, and any other device with suitable means of agitation and liquid spray-on. Methods of agitating, mixing, and agglomerating paniculate components are well-known to those skilled in the art. The apparatus may be designed or adapted for either continuous or batch operation as long as the essential process steps can be achieved. Once agglomerated, the product preferably goes through a conditioning step. Conditioning is defined herein as that processing necessary to allow the base granule to come to equilibrium with respect to temperature and moisture content. This could involve drying off excess water introduced with the liquid binder via suitable drying equipment including fluidized beds, rotary drums, etc. The free moisture content of the base granule should be less than about 10%, preferably less than about 5%. As used herein, free- moisture content is determined by placing 5 grams of a sample of base detergent granules in a petri dish, placing the sample in a convection oven at 50°C (122°F) for 2 hours, followed by measurement of the weight loss due to water evaporation. If the liquid binder does not introduce an excess of water, conditioning may involve merely allowing time to reach equilibrium before admixing additional ingredients. In cases where the compositions contain hydratable salts, it is preferable to hydrate them prior to the agglomeration step using the hydratio' process described in, e.g. U.S. Patent No. 4,427,417 issued January 24, 1984 to Porasik, incorporated herein by reference. After agglomeration the final step is to admix the agglomerated granules with other optional detergent ingredients, such as solid silicate and bleaching agent, using any suitable batch or continuous pr> cess as discussed hereinabove. Optional process steps include screening and/or pre-mixing of dry detergent ingredients before agglomeration, pre-hydration of hydratable salts, and screening and/or grinding of the base granule or final product to any desired particle size. Concentrated automatic dishwashing detergent compositions are preferred herein. Compositions containing greater than about 60% active ingredients, preferably between about 70% and about 95% active ingredients are preferred. Preferably, from about 5% to about 98%, most preferably from about 10% to about 50%, of the automatic dishwashing detergent composition is detergency builder, and from about 2% to about 80%, preferably from about 20% to about 40%, is spray dried granules comprising silicate and water-soluble organic polymer. As used herein, all percentages, parts, and ratios are by weight unless otherwise- stated. - The following nonlimiting Examples illustrate the process of the invention and facilitate its understanding. EXAMPLE I The following compositions are prepared by first forming spray dried granules followed by admixing the remaining dry ingredients. The components are set forth in Table 1. Table 1 Wt. % of Detergent Composition A Spray Dried Granule Components: Sodium polyacrylate 4.29 Alkali Metal Silicate 10.26 Sodium carbonate 14.28 Final Product Ingredients Spray Dried Solid Granule 28.83 Sodium carbonate 14.03 Sodium sulfate 8.23 Sodium citrate 14.28 Nonionic surfactant (1) 3.62 Hydrous sodium silicate (2) 18.16 Bleach 2.65 Water —balance- ((11)) BBlleenndd,, bbyy wweeiigghhtt ooff ttoottaall ssuurrffaaccttaanntt,, ooff 338.7% monohydroxy (C ) lo alcohol which has been ethoxylated with 8 moles of ethylene oxide per mole of alcohol, 58.1 % of polyoxypropylene/polyoxethylene reverse block polymer and 3.2% monostearylacid phosphate. (2) 2.0 ratio SiO :Na O Britesil® H2O. 2 2 EXAMPLE II The automatic dishwashing detergent compositions set forth in Table 2 are prepared by (a) spray drying alkali metal silicate and water soluble organic polymer with other components; (b) agglomerating and fluid bed drying the spray dried granules with various detergent ingredients and (c) admixing solid silicate and/or bleach. Table 2 Wt. % of Detergent Composition B C D Sprav Dried Granule Components: Sodium polyacrylate 5.56 5.56 5.56 Alkali Metal Silicate 13.30 13.30 17.88 Sodium carbonate 18.52 9.26 6.17 Nonionic surfactant(l) 4.78 4.78 Sodium sulfate 10.67 10.67 Polyacrylate Thickener(2) - 2.00 - Final Product Ingredients: Spray Dried Solid Granule 37.38 45.57 45.06 Sodium carbonate 9.26 12.35 Sodium sulfate 10.67 - - Sodium citrate 18.52 18.52 18.52 Nonionic surfactant (1) 4.7? - - Liquid silicate 9.94 9.94 10.65 Admix Hydrous sodium silicate (3) 5.06 5.06 - Bleach 3.44 3.44 3.44 Water Balance (1) Blend, by weight of total surfactant, of 38.7% monohydroxy (C ) alcohol which has been ethoxylated with 8 moles of ethylene oxide per mole of alcohol, 58.1 % of polyoxypropylene/polyoxethylene reverse block polymer and 3.2% monostearylacid phosphate. (2) Polygel DK, 3-V Chemical Corporation (3) 2.0 ratio SiO :Na O Britesil H2O. 2 2 The invention may be embodied in other specified forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range or equivalency of the claims are therefore intended to be embraced therein.

Claims: 1. A process for making high bulk density granular automatic dishwashing detergent composition comprising: (a) spray drying a mixture comprising from 20% to 90%, by weight of said mixture, of neutralized or alkali metal silicate solution and from 5% to 30%, by weight of said mixture, of water-soluble organic polymer solution to form free flowing granules; and (b) combining from 20% to 80%, by weight of said composition, of said granules of step (a) with from 1% to 90% of a non-phosphate detergent builder; wherein said composition having a bulk density of greater than 0.7 grams/cc and less than 0.5% phosphate in the form of phosphorous. 2. The process of Claim 1 wherein step (a) comprises from 40% to 70% of said alkali metal silicate solution from 20% to 80% of said non-phosphate detergency builder. 3. The process of Claim 1 or 2 wherein said combining of step (b) is by agglomerating, spray drying, dry mixing or combinations thereof, preferably agglomerating or dry mixing. 4. The process of any one of the preceding claims wherein said detergency builder is selected from the group consisting of water-soluble, alkali metal, ammonium or substituted ammonium carbonates, borates, polyhydroxysulfonates, polyacetates, carboxylates, polycarboxylates and mixtures thereof, preferably from 15% to 20% sodium carbonate and from 8% to 20% sodium citrate. 5. The process of any one of the preceding claims wherein step (a) further comprises from 0.1% to 10% of a low foaming nonionic surfactant comprising a Cιg.2θ straight chain alcohol condensed with an average of from 6 to 15 moles of ethylene oxide per mole of alcohol, preferably a C^g alcohol condensed with an average of from 7 to 9 moles of ethylene oxide per mole of alcohol. 6. The process of any one of the preceding claims wherein said water-soluble organic polymer of step (a) is selected from the group consisting of aqueous solutions of alkali metal salts of polyacrylates with an average molecular weight in acid form of from 1,000 to 10,000, and acrylate/maleate or acrylate/fumarate copolymers with an average molecular weight in acid form of from 2,000 to 80,000 and a ratio of acrylate to maleate or fumarate segments of from 30: 1 to 2: 1, and mixtures thereof. 7. The process of any one of the preceding claims wherein said alkali metal silicate solution comprises from 30% to 60% water and said water-soluble organic polymer solution comprises from 10% to 70% water. 8. The process of any one of the preceding claims further comprising step (c) admixing in an amount of bleach sufficient to provide the composition with 0.1% to 5% of available chlorine or available oxygen based on the weight of the detergent composition, preferably the chorine bleach is chlorocyanurate. 9. The process of any one of the preceding claims wherein said alkali metal silicate has a ratio of Siθ2:M2θ of from 1.6 to 3.0:1, preferably from 2.0:1 to 2.4:l.wherein M is K + or Na + or mixtures thereof. 10. The process of any one of the preceding claims wherein s * low foaming nonionic surfactant of step (a) further comprises a polyoxypropylene, polyoxyethylene block polymeric compound and/or from 2% to 20% of an alkyl phosphate ester suds suppressor. 11. The process of any one of the preceding claims wherein said granules of step (a) are agglomerated in step (b) with said detergency builder and from 3% to 45%, of a liquid binder selected from the group consisting of water, aqueous solutions of alkali metal salts of polycarboxylic acid, liquid silicate, nonionic surfactant, and mixtures thereof and wherein in step (b) further comprises anionic surfactants selected from the group consisting of alkyl sulfonates containing from 8 to 20 carbon atoms, alkyl benzene sulfonates containing from 6 to 13 carbon atoms in the carbon atoms in the alkyl group and the mono- and/or dialkyl phenyl oxide, mono and/or di-sulfonates wherein the alkyl groups contain from 6 to 16 carbon atoms, and mixtures thereof. 12. The process of any one of the preceding claims whereir from 40% to 70% of said polyoxypropylene, polyoxyethylene block polymeric compound is 75%, by weight of the compound, of a reverse block co-polymer of polyoxyethylene and polyoxypropylene containing 17 moles of ethylene oxide and 44 moles of propylene oxide; and 25%, by weight of the compound, of a block co-polymer of polyoxyethylene and polyoxypropylene, initiated with trimethyl propane, containing 99 moles of propylene oxide and 24 moles of ethylene oxide per mole of trimethylol propane.

Inventors: JOLICOEUR JOHN MICHAEL, WANDSTRAT EDWARD JOSEPH, JOLICOEUR, JOHN, MICHAEL, WANDSTRAT, EDWARD, JOSEPH
Applicants: PROCTER & GAMBLE, THE PROCTER & GAMBLE COMPANY
Application year: 1994
Main classification: C11D3
IPC codes: C11D3, C11D11, C11D17